Freeze drying is like making your food waterproof and light as a feather. Imagine you have a yummy piece of fruit that you want to keep forever. You don't want it to go bad, but you also don't want to weigh down your backpack by carrying a heavy container of it. That's where freeze drying comes in!
First, we put the fruit into a special machine called a freeze dryer. This machine freezes it really quickly, so fast that the water inside turns into ice and becomes solid. This helps to keep the fruit fresh and prevent any bacteria from growing.
Next, the freeze dryer starts to heat up, but not in the way we usually heat things up. Instead of adding heat, the machine takes the water that was frozen and turns it into vapor. It literally sucks the water out of the fruit! This is called sublimation.
Finally, after the freeze dryer has removed all the water from the fruit, it goes through one last step of drying at a low temperature, just to make sure that any remaining moisture is removed. The result is a super lightweight and crispy piece of fruit that will last a very long time.
So, freeze drying is like magically removing all the water from your food without changing its taste or texture, making it easy to store and carry with you.